If you’ve been following my work the last couple of months you have probably noticed there are a lot of myths out there in the fitness world. Some of them made a lot of sense before doing the research, such as the importance of exercise-induced hormones (or the lack thereof) while others I’ve never thought made a lot of sense and look to see if research backs it up. That’s what I have in store for today, and that’s looking at the idea that you need to keep your weight-lifting sessions under an hour. Will you really jeopardize your gains if you go over and less is really more or could you be short-changing yourself by doing so?
Where did this magic one hour window come from anyway? This is what I set out to search for to begin my research for this article. It was pretty simple, just find multiple articles explaining why you need to keep training under an hour and see what their explanation was. There was plenty of this out there, so what was the most common reasoning? For the most part it all came down topics I’ve recently reviewed, how very convenient for me. They concluded since cortisol levels rise and testosterone levels fall after about an hour of training and since cortisol is catabolic and testosterone is anabolic this is the main reason. We don’t want catabolic hormones taking over and our anabolic ones depleted, obviously right? If you’ve been paying attention, I’ve already taught you high levels of cortisol from training are only indicators that you had an effective workout and exercise-induced testosterone has no effect on muscle-protein synthesis or hypertrophy. If that wasn’t enough the studies everyone pointed to were done on endurance athletes. Not exactly the same thing as strength athletes. I’d say that’s strike one for keeping exercise under an hour.
The next common reason to keep workouts under an hour was because if you workout for too long you will deplete all of your body’s glycogen stores and your body will start using muscle for fuel. This one makes little sense. If you have full glycogen stores in your muscles you have about 500 grams stored up. You are not going to burn through 500 grams of glycogen in an hour of working out no matter how hard you train. The utilization of carbs during exercise can be calculated from oxygen uptake and respiratory exchange ratio. The rate of oxidation depends on the intensity of the exercise as well as how well-trained the individual is. A well-trained person has a much higher capacity to metabolize glucose and fat compared to an untrained person. Romijn et al. 1993 (1) and Loon et al. 2001 (2) showed the major carbohydrate source used in exercise above 70% is muscle glycogen. Hermansen et al. 1967 (3) showed well-trained subjects can more than oxidize 3 grams per minute which means after an hour of very intense exercise that would be roughly 180 grams from carbohydrates. Strike two for keeping exercise under an hour.
The last reason out there to keep exercise under an hour is the common fear of overtraining. Overtraining seems to be everywhere now days, and I believe it has really been blown out of proportion. It seems like everyone is so worried about overtraining that as soon as they do anything that gives them sore muscles they think they need to take some time off so they don’t overtrain. Okay I’m not saying overtraining doesn’t exist, but realize that overtraining is the point where things like fatigue and feeling burnt out becomes chronic. Where the demands of training frequently outweigh the time for regeneration. Most of the time this happens because someone isn’t fueling their body properly and/or they aren’t getting enough rest. Then there is overreaching which is basically the short-term version of overtraining. I think many people also confuse these two things. Some programs such as Sheiko training are programmed to purposefully overreach and then go through a period of deloading where the gains are actualized. As long as you don’t overreach for too long (which in turn leads to overtraining) it can be used for our own good for strength and size. Not lifting for over an hour in fear of overtraining seems foolish at best, strike three you’re out!
This isn’t to say you have to go over an hour and there is nothing wrong with getting in and getting out, but if you were worried your body would go catabolic if you did workout over an hour, you can now lift worry free. As always genetics, goals and your own training protocols play a big role in how long and hard you should workout. As long as you are smart and listen to your body, and knock the weight down for a while when your body really needs it, you’ll be golden. What I am sure about, however, is that if you feel you need to workout longer than an hour to reach your goals you shouldn’t worry about it one bit.